Early-stage breast cancer is cancer only in the breast and possibly nearby lymph nodes. Surgery is the first treatment for early-stage breast cancer.

Metastatic breast cancer is cancer that has spread to parts of the body away from the breast, such as the bones, liver, brain, or lungs. When a woman is diagnosed with breast cancer for the first time and the cancer is metastatic, surgery to remove the primary cancer in the breast usually isn't done because the cancer has already spread. In these situations, the first treatment is medicine: chemotherapy, hormonal therapy, and/or targeted therapies. Radiation therapy also is used sometimes to shrink tumors.

A small Canadian study has found that women diagnosed with metastatic breast cancer (with no previous history of early-stage breast cancer) who had surgery to remove the primary tumor in the breast lived longer after diagnosis than women who didn't have the primary tumor removed.

The results were presented at the 2011 San Antonio Breast Cancer Symposium.

The researchers compared the outcomes of 64 women diagnosed with metastatic breast cancer who didn't have the primary cancer in the breast removed to the outcomes of 46 women diagnosed with metastatic breast cancer who had the primary cancer in the breast removed with mastectomy. None of the women had been diagnosed with breast cancer before.

Many of the women who had surgery opted for mastectomy for more practical reasons than to improve their prognoses. For example, they wanted to ease pain, or stop bleeding or draining fluid, or get rid of a foul odor coming from the breast tumor.

Only 15% of women who had surgery had later tumor growth in the breast area compared to 43% of women who didn't have surgery. Overall survival was 16 months longer for women who had surgery compared to women who didn't (49 months compared to 33 months):

Half the women who had surgery lived for more than 49 months and half lived for shorter periods of time.

Half the women who didn't have surgery lived for more than 33 months and half lived for shorter periods of time.

It's important to know that some of the women who didn't have surgery may have wanted it, but were considered too ill to have surgery. These women likely had a worse-than-average prognosis. This could have affected the study results since there may have been more women with a worse prognosis who didn't have surgery.

This small study suggests that some women many benefit from surgery to remove a primary breast tumor even when the cancer has already spread to parts of the body away from the breast. Still, surgery is not routinely done in this situation and is controversial among both surgeons and doctors who take care of breast cancer patients.

A larger, more comprehensive study is being done now to see if surgery to remove a primary breast tumor makes sense when breast cancer has already spread to areas away from the breast.

If you've been diagnosed for the first time with breast cancer that is metastatic and have never had the primary tumor in your breast removed, you'll work very closely with your medical team to choose a treatment plan that makes the most sense for your specific situation. You may want to ask your doctor about this study and whether surgery makes sense for you.